Diesel fuel for use with internal combustion engines is popular for reasons of availability, price and efficiency. Diesel engines are well known for durability and longevity. However, the use of such fuel is not problem free, particularly in colder climates. This is due at least in part to the presence of paraffin, wax and water in the fuel in varying degrees depending on the geographical source of the fuel and the amount of refinement. At approximately 20.degree. F., the paraffin can congeal and block the fuel filter with resultant engine starvation even after a period of engine operation. Water condensation can also cause engine problems.
In attempts to solve this problem, various devices have been used to heat the fuel prior to entry into or upon entry into the fuel filter to avoid congealing and permit the passage of the fuel to the fuel injectors. For example, some heaters are provided to preheat the fuel even while the engine is at rest in order to facilitate starting. Another device is interposed between the fuel filter mount and the fuel filter to heat the fuel as it passes into and out of the fuel filter. Many other devices have been proposed and are available for heating the fuel.